The present invention relates to a surgical light apparatus, and particularly a surgical light apparatus having improved cooling capability. More particularly, the present invention relates to a lighthead of a surgical light apparatus that blocks radiant heat energy from reaching a target area to be illuminated while providing for cooling of the lighthead.
Surgical lights used in hospital operating rooms to illuminate surgical sites on patients are known. Surgical lights employ one or more lamps, such as a tungsten halogen lamp, that convert electrical input to visible light. The conversion of electrical energy to light by a light bulb can be relatively inefficient, and over ninety percent of the input energy can be transmitted from the bulb as radiant heat.
The desirability of illuminating the target area to be lighted with cold light, that is, only visible light, is also known. Thus, surgical lights often include a filter in the lighthead to remove unwanted radiation, such as infrared radiation, so that only visible light is transmitted to the target area. For example, U.S. Pat. No. 4,254,455 to Neal, Jr. discloses a lighting device in which a curved reflector includes a dichroic coating that reflects only visible light. Removing heat energy radiation prior to illuminating the target area, however, can result in temperatures increasing within the surgical lighthead.
Thus, many known surgical lights provide a mechanism to remove unwanted heat from the surgical lighthead. In the above-identified patent to Neal, Jr., for example, the dichroic coating that reflects visible light allows heat energy to pass through the reflector to be radiated from the back of the lighthead. As another example, U.S. Pat. No. 4,254,454 to Hardin, Jr. discloses a lighting device in which airflow passages provide for cooling the lighting device by drawing external air through the lighting device.
Many surgical procedures use tools such as lasers and electro cautery units that periodically result in the generation of smoke during the surgical procedure. A surgical light fixture design that relies on flow of external air through the lighthead for cooling can cause the smoke to be drawn inside the lighthead, resulting in deposits from the smoke onto internal components. This can degrade the optical performance and require cleaning of the internal components.
According to the present invention, a surgical light apparatus has a light source and an enclosure surrounding the light source. The enclosure includes a reflector and a lens substantially transparent to visible light. The light source generates visible light and heat energy radiation. The surgical light apparatus includes at least one filter element formed at least in part from a material that is substantially transparent to at least a portion of visible light radiation and that substantially blocks transmission of heat energy radiation. The one or more filter elements are coupled to the enclosure and configured to block transmission of heat energy radiation from the light source to the reflector substantially over a 360° field of view about a longitudinal axis through the light source. The at least one filter element includes a first end longitudinally spaced from a second end and is configured to define at least one gap between the first and second ends.
The heat energy radiation can include infrared radiation. The at least one filter element can be configured to block radiation having a predefined range of wavelengths. According to another aspect of the invention, the gap can extend from the first end to the second end of the at least one filter element.
According to yet another aspect of the invention, the light source can include first and second light sources. The first light source has a first longitudinal axis and second light source has a second longitudinal axis that is spaced apart from and parallel to the first longitudinal axis. The at least one filter element is configured to block transmission of heat energy radiation from the first light source to the reflector substantially over a 360° field of view about the first axis and to block heat energy radiation from the second light source to the reflector substantially over a 360° field of view about the second axis.
According to still other aspects of the invention, the enclosure can be substantially sealed or hermetically sealed to prevent entry of air into the enclosure. The lens can be an acrylic lens and can be substantially transparent to heat energy radiation. The reflector can include an aluminum reflecting surface which furthermore can be opaque.
According to yet still another aspect of the invention, the at least one filter element comprises a plurality of filter segments. The filter segments can be configured as rectangular filter plates. The filter plates are spaced apart in a pattern to define gaps between each pair of adjacent filter plates.
According to another aspect of the invention, the reflector can be configured to reflect both visible light and heat energy radiation toward the lens. The reflector can be devoid of any coating that selectively filters visible light and heat energy radiation.
According to yet another aspect of the invention, the lens can be substantially transparent to visible light and to heat energy radiation. The lens can be devoid of any coating that selectively passes visible light and that blocks heat energy radiation.
According to still another aspect of the invention, an apparatus for cooling a surgical light fixture has a light source and an enclosure surrounding the light source. The enclosure includes a reflector configured to reflect light from the light source towards a lens that is transparent to visible light. The apparatus includes a plurality of filter elements coupled to the enclosure between the light source and the reflector. The filter elements are formed at least in part from material that is substantially transparent to visible light radiation and that substantially blocks transmission of heat energy radiation. The filter elements are configured to intersect substantially all radiation from the light source that otherwise would pass to the reflector and through the lens. The filter elements are configured to define at least one gap between two adjacent filter elements.
According to yet still another aspect of the invention, the filter elements can be configured to provide a gap between each pair of adjacent filter elements. The filter elements can be rectangular filter plates. Each filter plate can have substantially the same shape.
According to another aspect of the invention, the plurality of filter elements can include a first set of filter plates and a second set of filter plates. The first set of filter plates is interleaved with the second set of filter plates so that each filter plate of the first set of filter plates is adjacent two filter plates of the second set of filter plates. The adjacent filter plates are separated by a gap. The first set of filter plates is arranged in a first pattern and the second set of filter plates is arranged in a second pattern spaced radially outward of the first set of filter plates.
According to still another aspect of the invention, the plurality of filter elements can include four inner filter plates spaced apart in a first square pattern and four outer filter plates spaced apart in a second square pattern located radially outward of the first square pattern. The second square pattern is rotationally offset from the first square pattern by about 45°.
According to yet still another aspect of the invention, the plurality of filter elements can include a plurality of filter plates. Each filter plate has a front, a back, a first side edge, and a second side edge. The plurality of filter plates are arranged in a pattern around the light source with the front of each filter plate facing toward the light source and the back of each filter plate facing away from the light source. The first side edge of each filter plate is spaced apart from the second side edge of an adjacent filter plate and located radially inward toward the light source from the second side edge of the adjacent filter plate.
According to another aspect of the invention, a surgical light apparatus includes a pivoting arm assembly and a lighthead coupled to an end of the pivoting arm assembly. The lighthead includes a housing, a light source, a lens, a reflector configured to reflect light from the light source through the lens, and a filter element. The filter element is coupled between the reflector and the light source to intersect substantially all radiation emanating from the light source toward the reflector. The filter element is configured to block heat energy radiation and to pass visible light. The filter element has at least two segments spaced apart to define an air gap therebetween.
According to yet another aspect of the invention, the filter element can include a plurality rectangular filter plates arranged in a pattern to provide a gap between each pair of adjacent filter plates. The plurality of filter plates can include a first plurality of filter plates arranged in a first pattern and a second plurality of filter plates arranged in a second pattern positioned radially outward of the first pattern. The plurality filter plates can include four inner filter plates spaced apart in a first square pattern and four outer filter plates spaced apart in a second square pattern positioned radially outward of the first square pattern and rotationally offset from the first square pattern by about 45°.
According to still another aspect of the invention, an apparatus for cooling a surgical light fixture having a light source and an enclosure surrounding the light source is provided. The enclosure includes a reflector configured to reflect light from the light source towards a lens that is transparent to visible light. The apparatus includes a filter coupled to the enclosure, the filter including means for blocking heat energy radiation emitted from the light source and means for permitting air flow between the reflector and the light source.
Additional features of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of the presently perceived best mode of carrying out the invention.